In the night sky: Orion
In the night sky: Orion

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Free course

In the night sky: Orion

1.3.1 Gaia mission

The European Space Agency launched a mission in 2013 to study the stars. The mission is called Gaia.

Gaia’s main objective is to measure the position of 1 billion (1,000,000,000) stars, and measure the speed that they move at, creating a 3D map of the Galaxy. This will be the largest dataset so far, and will provide astronomers with a wealth of information covering a wide range of research fields: from Solar System studies, galactic astronomy, and cosmology to general relativity.

Download this video clip.Video player: ou_futurelearn_orion_vid_1026.mp4
Skip transcript


60 Second Adventures in Astronomy. Number thirteen, Taking a Galactic Census.
How do you take a census in space?
Keeping track of millions of stars is quite a tricky job, especially as they are constantly moving.
Luckily the new Gaia spacecraft is coming to the rescue from a position of about one and a half million kilometers from the earth - ready to do a whole lot of measuring.
With its two optical telescopes, Gaia will be able to map over a billion stars by measuring minute changes of position against the background of other stars this is known as parallax.
And, as well as measuring how old and bright they are, by measuring their Doppler shifts, it can tell us whether those stars are moving towards us or away from us.
And if that’s not impressive enough, by measuring the bending of starlight by the sun’s gravitational field, it will be able to test Einstein’s theory of General Relativity.
In the end Gaia will deliver us a map of the Galaxy. And not just any map - it will be in 3D, show us how everything is moving, and help us get a better understanding of how the whole thing began and where it’s heading.
So, taking a census in space will be a much more realistic proposition.
End transcript
Interactive feature not available in single page view (see it in standard view).

In the next section, you’ll find out about The Open University’s involvement with Gaia.


Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to University-level study, we offer two introductory routes to our qualifications. You could either choose to start with an Access module, or a module which allows you to count your previous learning towards an Open University qualification. Read our guide on Where to take your learning next for more information.

Not ready for formal University study? Then browse over 1000 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus371